I wasn't considering new UTXOs as new monetary units, I was referring to the sum of all bitcoin existant on-chain. What I mean is that all bitcoin units come into existence through proof of work, not that all proof-of-work cause new bitcoin to come into existence. The transaction fees are the block reward in addition to the new (created/issued) bitcoin, and proof-of-work is expressed for the fee portion as much as for the issuance portion. Theoretically at some point in the future, when the tx fees reliably exceed the issuance, the hashrate might synamically vary block-by-block depending on total available fees in the mempool.